Digital elevation models (DEM) are increasingly used for landform mapping, particularly with the growing availability of national and global datasets. In this paper we describe a variety of techniques that can visualise a DEM. We then compare five techniques to ascertain which performs the most complete and unbiased visualisation. We assess the visualisation techniques by comparing landforms mapped from them against a detailed morphological map (derived from mapping of multi-azimuth relief-shaded DEMs cross-checked with stereo aerial photographs). Results show that no single visualisation method provides complete and unbiased mapping. The relief-shaded visualisations are particularly prone to azimuth biasing, although they can highlight subtle landforms. We recommend curvature visualisation for initial mapping as this provides a non-illuminated (and therefore unbiased) image. Initial mapping can then be supplemented with data from relief-shaded visualisations.